Rubber-metal spring unit

ABSTRACT

A rubber-metal spring unit is for use in bogies of rail vehicles, wherein the rubber-metal spring unit is arranged between an upper connection element, which is connected to the sprung mass, and a lower connection element, which is connected to the unsprung mass. The rubber-metal spring unit is configured as a conical layered spring composed of multiple alternately and concentrically arranged layers of elastomer material or rubber, on the one hand, and metal, on the other hand. The individual layers are formed as conical annular-shaped bodies, wherein the two conical surfaces of at least one of the conical annular-shaped bodies have different cone angles in relation to the common vertical axis of the concentric layers of rubber and metal which form the conical layered spring.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of international patent application PCT/EP2016/077940, filed Nov. 17, 2016, designating the United States and claiming priority from German application 10 2015 224 744.9, filed Dec. 9, 2015, and the entire content of both applications is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a rubber-metal spring unit, in particular for use in running gears of rail vehicles, wherein the rubber-metal spring unit is arranged between an upper connection element, which is connected to the sprung mass, and a lower connection element, which is connected to the unsprung mass, and which is constructed as a conical layered spring composed of multiple alternately and concentrically arranged layers of elastomer material or rubber, on the one hand, and metal, on the other hand.

BACKGROUND OF THE INVENTION

In the drawings, FIG. 2 shows a spring unit of this type from the prior art.

Rubber-metal spring units for rail vehicles in particular are, owing to the demands placed thereon with regard to the stiffnesses and stabilities to be achieved during deformation, commonly composed of a combination of layered and conical springs. These are generally conventional and known. Here, the layered spring provides the lateral mobility. The conical spring permits primarily vertical mobility with set stiffnesses, which are responsible in particular for the protection of the train against derailment. Layered springs are commonly composed of multiple layers divided horizontally by intermediate plates. Conical springs are commonly composed of multiple conically inclined layers which are divided by intermediate plates. The intermediate plates have a uniform material thickness.

Disadvantages of this structural form are:

-   -   The use of two components which, owing to their functional         division, require a considerably greater structural space, in         particular in the vertical direction.     -   It is necessary for two vulcanization molds to be provided         (costs).     -   Twice the vulcanization time is required on one press.     -   The connecting elements between the two components must be         subjected, in a relatively cumbersome manner, to cutting         machining (higher weight, more expensive components).     -   The connecting elements must be installed in a secure and         corrosion-protected manner (installation effort, risk of         corrosion).     -   Owing to their structural form, such combinations have a         tendency to tilt in the event of lateral deformation. This has         an adverse effect on the usability of the component.

Other rubber-metal elements, such as for example barrel springs, require considerably more structural space, in particular in terms of diameter, owing to their large unattached rubber surface, can be adjusted little in terms of their vertical spring characteristics, and also have a tendency to tilt in the event of lateral deflection.

SUMMARY OF THE INVENTION

For the invention, it is thus an object to permit the good technical characteristics (mobility, easily adjustable different lateral and vertical stiffnesses) of a conical and layered spring combination in a very compact structural form with considerably lower weight, less technical effort in terms of production/installation, and at the same time better corrosion resistance.

It is furthermore sought to avoid the disadvantageous characteristic of layered springs having lateral stiffnesses which decrease with increasing vertical load (softening under stress or load), because the resulting adverse effect (load and deflection instability), in particular for air spring systems, limits the usability of the components, in particular those of air spring systems.

A rubber-metal spring unit is arranged between an upper connection element, which is connected to a sprung mass, and a lower connection element, which is connected to an unsprung mass. The rubber-metal spring unit includes: the spring unit being configured as a conical layered spring composed of multiple alternately and concentrically arranged layers of elastomer material or rubber, on the one hand, and metal, on the other hand; and, the individual ones of the layers being formed as conical annular-shaped bodies, wherein the two conical surfaces of at least one conical annular-shaped body have different angles or cone angles in relation to the common vertical axis of the concentric layers of rubber and metal which form the conical layered spring.

Here, the individual layers are formed as conical annular-shaped bodies, wherein the two conical surfaces of at least one of the conical annular-shaped bodies have different cone angles in relation to the common vertical axis of the concentric layers of rubber and metal which form the conical layered spring.

The individual rubber layers of the compact spring are, in accordance with their desired function, arranged with different layer angles and layer diameters. This is made possible through the use of connecting elements which, by contrast to the classic plates, have a different geometry in relation to the individual rubber layers.

The differences may comprise different angles and/or diameters, or freely contoured surfaces at each connecting surface. Owing to a practical combination of different layers, not only can softening under stress and thus an increased susceptibility to tilting be avoided, but it is even the case that a stabilizing effect arises (opposite tilting in the event of lateral deflection owing to the geometry), by means of which it is even possible for tilting effects from an air spring that may be connected in series to be compensated. This considerably increases the usability of air spring systems in the event of lateral deflection (more load and more deflection are possible).

One advantageous embodiment is that at least one of the conical surfaces of at least one conical annular-shaped body has a structured shape or undulating shape which deviates from a smooth hollow cone, preferably over the entire cone circumference. In this way, the spring can be adapted to a particular form of use, and a reduction of the tilting or buckling tendency can be achieved. This is the case in particular in conjunction with a further advantageous embodiment, which consists in that the conical surfaces of at least two conical annular-shaped bodies vulcanized onto one another have, over their cone circumference, a structured shape or undulating shape which deviates from a smooth hollow cone.

A further advantageous embodiment is seen in that the alternately and concentrically arranged layers of elastomer material and metal have layer thicknesses which vary from the inside to the outside over their cone profile. In particular if the layer thickness of at least one concentrically arranged layer is formed so as to be smaller at its inner diameter than at its outer diameter, this yields an increased supporting moment provided by the rubber-metal spring unit configured in this way, such that a reduced tilting and buckling tendency arises owing to a stabilizing effect of the different layers in the event of lateral deformation. In this way, the tilting moment of the air spring in the event of lateral deflections is compensated. The result is thus a considerably increased linear characteristic of the air spring system in the event of lateral deflections, and instability of the air spring system is avoided. In this way, air spring systems of the same structural size can be operated with greater loads and lateral deflections.

A further advantageous embodiment consists in that the alternately and concentrically arranged layers of elastomer material and metal have different cone angles or layer angles, in particular if one considers the average cone angle, that is, the average between the different cone angles of the inner and outer surfaces of the individual conical annular-shaped bodies. This further increases the linear characteristic of the air spring system, whereby traveling comfort is increased. Protection against derailment is also increased, because the stiffnesses in the event of small lateral deflections are reduced.

In the embodiment according to the invention, softening under load and stress is avoided by means of higher vertical loads in the event of lateral deflection.

There is also less wear (abrasion) of the air spring at the rim seat and of the bead ring clamping point owing to a parallel movement of the upper and lower clamping points. By means of these parallel movements of the upper and lower clamping points, lower stresses arise in the air spring, self-evidently also resulting in an increased service life.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings wherein:

FIG. 1 shows an embodiment according to the invention of the rubber-metal spring unit; and,

FIG. 2 shows a unit of this type from the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 shows an embodiment according to the invention of the rubber-metal spring unit for use in the bogie of a railbound vehicle. The rubber-metal spring unit is arranged between an upper connecting element 2 and a lower connecting element 1. The upper connecting element 2 is connected to the chassis or mass which is spring supported and the lower connecting element 1 is connected to a mass which is not spring supported and can be in the form of an undercarriage or bogie. The rubber-metal spring unit is configured of a conical layered spring of several alternating and concentrically arranged layers of elastomeric material such as rubber, on the one hand, and metal 3, 4, on the other hand. The elastomeric material or rubber is arranged between each two of the connecting elements 1, 2 and the metal layer 3, 4.

The individual layers of elastomer material and of metal are configured as conically-shaped annular bodies. The two conical surfaces of at least one conically-shaped annular body 4 have different angles or conical angles with reference to the common vertical axis of the concentric layers forming the conical layered spring made of rubber and/or metal.

For example, the layer 4 of metal has different layer thicknesses over its conical extent from inside to outside. There, the layer thickness is at least configured to be smaller at least at the inner diameter of layer 4 than at the outer diameter thereof.

It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims. 

What is claimed is:
 1. A rubber-metal spring unit arranged between an upper connection element, which is connected to a sprung mass, and a lower connection element, which is connected to an unsprung mass, said rubber-metal spring unit comprising: the spring unit being configured as a conical layered spring composed of multiple alternately and concentrically arranged layers of elastomer material or rubber, on the one hand, and metal, on the other hand; and, the individual ones of said layers being formed as conical annular-shaped bodies, wherein the two conical surfaces of at least one conical annular-shaped body have different angles or cone angles in relation to the common vertical axis of the concentric layers of rubber and metal which form the conical layered spring.
 2. The rubber-metal spring unit of claim 1, wherein at least one of the conical surfaces of at least one conical annular-shaped body has a structured shape or undulating shape which deviates from a smooth hollow cone, preferably over the entire cone circumference.
 3. The rubber-metal spring unit of claim 1, wherein the conical surfaces of at least two conical annular-shaped bodies vulcanized onto one another have, over their cone circumference, a structured shape or undulating shape which deviates from a smooth hollow cone.
 4. The rubber-metal spring unit of claim 1, wherein the alternately and concentrically arranged layers of elastomer material and metal have layer thicknesses which vary from the inside to the outside over their cone profile.
 5. The rubber-metal spring unit of claim 4, wherein the layer thickness of at least one concentrically arranged layer is formed so as to be smaller at its inner diameter than at its outer diameter.
 6. The rubber-metal spring unit of claim 1, wherein the alternately and concentrically arranged layers of elastomer material and metal have different cone angles or layer angles.
 7. The rubber-metal spring unit of claim 1, wherein said sprung mass is the chassis of a railway vehicle; and, said unsprung mass is a bogie of the railway vehicle. 